Plant Cell
“Then God said, "Let the earth bring forth grass, the herb [that] yields seed, [and] the fruit
tree [that] yields fruit according to its kind, whose seed [is] in itself, on the earth"; and it
was so. And the earth brought forth grass, the herb [that] yields seed according to its kind, and
the tree [that] yields fruit, whose seed [is] in itself according to its kind. And God saw that [it
was] good.” Gen 1:11-12
Plant cells are eukaryotic cells that differ in several key respects from the
eukaryotic organisms. Their distinctive features include:
cells of other
vacuole, a water-filled volume enclosed by a membrane known as the

A large central

tonoplast maintains the cell's turgor (osmotic pressure enabling stiffness of
plant), controls movement of molecules between the cytosol and sap, stores useful
material and digests waste proteins and organelles.
cell wall composed of cellulose and hemicellulose, pectin (used in food as a
gelling agent particularly in jams and jellies. It is also used in fillings, medicines,
sweets, as a stabilizer in fruit juices and milk drinks and as a source of dietary
fiber), and in many cases lignin, is secreted by the protoplast on the outside of the
cell membrane. This contrasts with the cell walls of fungi (which are made of chitin),
and of bacteria, which are made of peptidoglycan.
 A
plasmodesmata,[3] pores in the
primary cell wall through which the plasmalemma and endoplasmic reticulum[4] of
 Specialized cell–cell communication pathways known as
adjacent cells are continuous.

Plastids, the most notable being the chloroplasts, which contain chlorophyll and the
biochemical systems for light harvesting and photosynthesis, but also amyloplasts
specialized for starch storage, elaioplasts specialized for fat storage, and
chromoplasts specialized for synthesis and storage of pigments. As in mitochondria,
which have a genome encoding 37 genes, [5] plastids have their own
genomes of about 100–120
unique genes[6] and, it is presumed, arose as prokaryotic endosymbionts living in the
cells of an early eukaryotic ancestor of the land plants and algae.[7]
 photosynthesis equation:
proteins called
photosynthetic reaction centers that contain chlorophylls. In plants, these proteins
are held inside organelles called chloroplasts, while in bacteria they are embedded in
the plasma membrane. Some of the light energy gathered by chlorophylls is stored in the
form of adenosine triphosphate (ATP). The rest of the energy is used to remove
electrons from a substance such as water. These electrons are then used in the reactions
 the process always begins when energy from light is absorbed by
that turn carbon dioxide into organic compounds. In plants, algae and cyanobacteria, this is
done by a sequence of reactions called the Calvin cycle, but different sets of reactions
reverse Krebs cycle in Chlorobium. Many
photosynthetic organisms have adaptations that concentrate or store carbon dioxide. This
helps reduce a wasteful process called photorespiration that can consume part of the
are found in some bacteria, such as the
sugar produced during photosynthesis.
Activity
plant cell observations
Homework
p. 263 #1, 18, 19
plant cell diagram